1. Field of the Invention
This invention relates to a coiler-furnace unit comprising a coiler mandrel which is disposed within a heat-insulating housing and adapted to be heated by means of a heating tube that is adapted to be axially moved to a position in which the heating tube surrounding the coiler mandrel.
2. Description of the Prior Art
To avoid formation of scale of the strip coiled on the coiler mandrel by the heat of the hot gases supplied to the coiler-furnace unit, it is known from Austrian Pat. No. 373,290 to heat up the coiler mandrel by means of a heating tube, which is provided with electric heating means and can be axially pushed over the coiler mandrel. The coiler mandrel is heated by means of the heating tube and then serves to heat the strip, which is wound on the coiler mandrel when the heating tube has been pulled from the mandrel. As result, the coil formed by the strip is heated by heat conducted from the inside. Whereas it is simple to heat the coiler mandrel by an induction winding provided in the heating tube, that operation requires a suitable source of electric power. Besides, the coil-receiving chamber which is confined in the unit by the heat-insulating housing is not heated so that heat is dissipated by radiation and convection from the coil of strip which is to be heated.